Hair straightener



FIG. 1 is a front, right side, top perspective view of a hair straightener showing our new design;

FIG. 2 is a rear, left side, bottom perspective view thereof;

FIG. 3 is a front elevational view thereof;

FIG. 4 is a rear elevational view thereof;

FIG. 5 is a left side elevational view thereof;

FIG. 6 is a right side elevational view thereof;

FIG. 7 is a top plan view thereof;

FIG. 8 is a bottom plan view thereof; and,

FIG. 9 is a front, right side, top perspective view thereof with the two sections of the hair straightener disposed in a partially open state.

The broken lines depict portions of the hair straightener that form no part of the claimed design. 

CLAIM The ornamental design for a hair straightener, as shown an described. 